Articulated and universal joint for propellers and other mechanisms



H. MURPHY ARTICULATED AND UNIVERSAL JOINT FOR PROPELLERS AND OTHER MECHANISMS ,W Rm, SY f/ my. E. 1 4 my .//////////4 mdf w ay o a A 2 z w J o 10 j M if .\h. y 12 June 21, 1949.

Filed Dec. 11, 1943 June 21, 1949- H. MURPHY 2,473,899

ARTICULATED AND UNIVERSAL JOINT FOR PROPELLERS AND OTHER MECHANISMS Filed D-eG. ll, 1943 3 SheeLS--Sheeil 2 ATTORNEY June 2l, 1949. H. MURPH 2,473,899

A CULATED AND UNIVERS JO FOR OPELLERS AND OTHER MECHA MS Filed Dec. 11, 194s K s sheets-sheet s ATTOR N EY Patented June 21, 1949 UNITED ARTICULATED AND UNIVERSAL JOINT FOB PROPELLERS AND OTHER MECHANISMS Howard Murphy, Glen Ridge, N. J., llnor to Curtiss-Wright Corporation, a corporation of Delaware Application December 11, 1943, Serial No. 513,982

12 Claims.

This invention relates primarily to universal and articulated joints or couplings, and especially to devices of this type that are required to sustain unusually heavy longitudinal loads in relation to their size.

Heretofore all such joints and couplings have been so constructed that the component parts thereof are arranged to slide relatively to each other. This is true whether the component parts are hinged or are formed into any type of cylindrical, conical, spherical or other description of bearing. In such constructions the sliding contacting surfaces frequently seize, or become abraded or excoriated under the action of heavy loads, which results in failure of the joint or coupling.

Attempts have been made to overcome this objectionable action by the use of ball, roller and other types of anti-friction elements interposed between the relatively sliding surfaces of the joint. While such arrangements function satisfactorily under light loads in the case of cylindrical and conical bearings, they are not practical in the case of spherical bearings. Under all circumstances, however, these types of anti-friction bearings require considerable space, and consequently it is rarely feasible to use the large sizes that are required for heavy loads.

With the above in mind, the principal object of this invention is to provide an articulated or universal joint which does not include any of the undesirable features enumerated and which is particularly adapted to sustain heavy longitudinal loads without undue wear or other deleterious action.

A further object is to provide a joint of the above type which requires exceptionally small space in relation to the magnitude of the sustained load it is capable of carrying.

A still further object is to provide constructions which are simple, rugged, reliable and compact and which can be manufactured at low cost by ordinary machining processes.

A still further object is to accomplish these ends without any sliding action between the pressure surfaces of the joints which sustain longitudinal loads.

A still further object is to provide joints of the character described wherein the longitudinal loads are sustained entirely, or substantially so, by component members adapted to roll one on the other without any relative sliding movement therebetween.

A still further object is to provide joints of the above description which are adapted to transmit (Cl. Nil-160.52)

2 torque loads, without appreciable lost motion, simultaneously with heavy longitudinal loads.

A still further object is to provide means for preloading joints constructed along these lines. so as to prevent undue longitudinal movement whenthe load to be supported is applied.

The above and other objects and novel features of the invention will appear more fully hereinafter from the following detailed description when taken in connection with the accompanying drawings. wherein two embodiments of the present invention are illustrated. It is to be expressly understood, however, that the drawings are for purposes of illustration only and are not designed as a deilnition of the limits of the invention, reference being had for this purpose to the appended claims.

Obviously, universal and articulated joints of the character mentioned are adapted for use in a wide field cf mechanical equipment, devices and appliances, and it is, therefore, the purpose of this invention to provide constructions which may be utilized in any industry or in any description of mechanism where movable joints are or can be advantageously employed.

The accompanying drawings show only one of the many uses and applications for such joints, namely, one in the airplane propeller industry, where the problem of securing rotatable blades to the hub of a variable pitch propeller is always a difficult one, and is especially so if provision be made for permitting each blade to swing in its socket as well as to pivot or turn therein about its longitudinal axis. The pivotal motion is necessary for the alteration of blade pitch, and the swinging motion, which may be either hingelike or universal, is desirable in order to reduce or eliminate bending stresses in the blade shank.

It is particularly desirable to provide for this swinging motion in the case of the larger and heavier sizes of blades because of the severe bending stresses that are otherwise developed in their Shanks. Heretofore, however, no practical solution of the problem has been found, due to the fact that excessively high centrifugal forces act on such blades during rotation of the propeller on which they are mounted. This will be readily comprehended when it isrealized that these forces range up to 200,000 pounds pe blade and may at times run even higher.

To those familiar with the propeller art it is obvious that space and weight limitations preclude the possibility of successfully using any type of articulated or universal ioint to support such forces, if there is any sliding action between the 2,473,899 3 4 supporting surfaceswhether such surfaces are in under consideration may be conveniently formed direct contact or have any usable sizes of ball or in the shape of a T-bolt as shown, but which for roller bearings interposed between them. On the l other purposes may be made in any shape adapted other hand, itis equally obvious that the direct to the transmission of thrust loads alonel or rolling action between the supporting surfaces, 5 thrust and torsion loads combined. A full sec` which is provided for by the present invention. tion of the adapter I8 is shown in the exploded y insures a compact; practical, high-capacity joint view, Fig. 3,-together with a side view'of the T- that meets the most extreme service' demands. .A bolt 2| and cooperating elements. v I Referring to the drawingsl wherein similarref- The T-bolt 2| has a head 22 and a shank secerence characters refer toA similar partsI through- 10 tion 23 which-.passes through the center of a ring out the several views: l 24. a blade or pitch changing gear 26, and a ring Fig.'1 is aview partly in section of a universal 2'!v of' compressible or pliant material such as propeller blade mounting and hub socket com, rubber, all of which 'are located between thefhead structed in accordance with the present-inven- "22 and the adapter I8. The inside surface 25 of tion, with the section plane taken substantially.1:5` the head `of the T-bolt 2| is substantially ilat parallel to the axis of the propeller shaft;

and engages a substantially cylindrical surface' Fig. 2 is a view partly in section of the elements 1 28, Figs. 1 and 3,.on the underside of the ring of the blade mounting and socket of Fig. 1, with 24,- thus providing vfor rolling motion of one of the section plane taken substantially perpendcthese surfaces on the other.l The cylindrical surular to the axis of thepropeller shaft; v20 face 28 is diametrically across the bottom of the Fig. 3 is an exploded view of the principalelering 24 and is preferablyy of long radius, in vthe g ments included in the propeller blade mounting neighborhood of eight to twelve inches or more; or anchoring arrangement of Figs. 1 and 2; the length 0f the radius depending in Part'upcn Figs. 4 and 5 aref'detail views of two locking the degree of swinging motion to be provided for keys or pins taken substantially on lines 4 4 and 25 the blade and in Dart Upon the extent 0f 01T- 5-5 of Figs. 1y andv 2, respectively; center movement which is permissible as a result Fig'. 6 is a sectional view of the detail of Fig. 5 of the rolling motion mentioned above. It is obv taken on line 6-6 thereof; vious that as the length of the radius is increased,

Fig. *'7 is a view somewhat similar to Fig. l the effective bearing area and capacity of thed showing -a propeller` blade mounted in accordance joint arel also increased, and. therefore, it 1S del with amodcation oftheninvven.tion; sirable to use as great a length as i's consistent Fig.A 8 is an exploded'view of theprincipal ele with practical limitations. The hole through the center of the ring 2l is tapered slightly, being of ingl'yf; anchored, thereinj '.Theg,propellerlhubis4 ring which cooperate for this purpose with oppo- 1de', `vV'ievvgrespeegreater diameter atv the top than at the bottoni un ngor-janchor- .Whclet iS properly proportioned to adequately g centraliz'eI the T-bolt 2| and at the same time ld2,wt`here is shown, v permit it to swingwithout sliding when rolling nlof theblade on the contact surface 28. To prevent rotation.

roelle'r =hub1with of the ring 24 relatively to the T-bolt 2|, a,- pair 'of a`propel1er=blade.rotatablyimoilntedfand'swing- 40 flanges 29 are provided on theundersideof the ndited'lgenerauy by `the ireferenevnumeral, |f| site sides of the' T-boltA head 22, as clearlyshownandfhasga central bore? |2 ,adapted fto receive a inFlgs. 1, 2, and 3.l

propellershaft and alplurality#ofjsubstantially The ringv 24,-which is slightly tapered on'itsf. radally'eiitending bladesocketssuchasll. Onlyl 45 Outside diametralvsurface, ts into a counterone ofthe bladensockets I3 isshown'inthe dawbore 3|) in the underside of the bladegear 26..

ings, .'theother socketsbeing yidentical tothe -onea The uppersur'face 3| 0f the ring is cylindrical,

showngypThe-central'borel2.of'they-,propeller hub`r with 4thevraxisof this vcylindrical surface,.. as

| ma'yffhave splinessuclill y to cooperate withsimilar splines onfthepropeller shaft so as to [forni effective driving.engagemrenw therewith. I f .1 y

The blade socket 3, Flgs'.f1-.and2, is open atp 'ring- 24 may bev substantially the same'gjag-the fion-the lower side thereof. The radiusfoflfthe Fig. 2,1 adapted l ,shown in `Figs. 1 and2, substantially at right' )angles tothe axis of the cylindrical surface-28 cylindrical surface 3l on the upper side-of 5 theits upper end to receive the blade shank- I6 whichjf f7 radius of the cylindrical surface 28 on the underis anchored therein-in a manner about to be de- 'V55 side thereof, though n0Y definite `relationship bescribed.v For the purpose of illustrating the printween them is required. f The cylindrical surface ciples of the invention, a hollow shank blade, 3| of ring 24 .cooperates 'with asubstantially such yas thatof. an` aeronautical propeller, is'f l at surface 32 at theendof the .counterbore shown `anchored in the blade socket 3. It will `3|) in the blade'r gear 26,"thu'sproviding for rolling f be obvious, however,` that the principles of the "motion -of one of these; surfacesVv von' the other. inventionl arenot limited vin `application to this The fit of the ring .2l in' the counterbore 3|! or any; other particular type of blade, nor to the is sulciently close toadequately `centralize one propeller"art, but may-be appliedto any descripy with the. other, but enough` clearancevis pro.. tion of mechanism whereinarticulated or uni- ,f vldedbetween the counterbore and the ring to Versal -joints are required to carryalongtudinal `65.-pernuit'lof free rolling movement `of the surface loads, andlespecially relatively heavy longitudinal 3|`on1thefsurface 32 without any slidingthereloads,"with or without torqueloads. f i 1 between #thejjtaper en -the outside diametral The blade shank I 6 is'- cylindrical, as is'fthe ,.Sulface-.Qfff'thc -ringllcocperating t0 Prevent blade socket|3,"and1has internal threads l.Itat d n'nterference'' with such rolling-movement the .lowerend thereof. 'A'. threadedy adapterf`,or Thedeptli'jofg-the.counterborefin the vbladfefgear reducer I ilV -is threaded intoj thefbladeshankQI6;` '-ijisV immaterialffexceptfto suitnspace requireand `has internal threads "l 9 arranged. to receive .i "f vThe center' hole' afthrough'the lblade the threaded end of a combinedf-thrustfand tor-v eariisfxislightlytaperedv and isslightly larger sion member, indicated generallyfby` `referente hanf Atheyl shank portion 23 ofthe T-.bolt 2I,'sov

numeralwZl, which for the specificjeconstruction[fasfto-'permitthelatter'toswing toythelin'iit.pro-` vided by the central bore in ring 24. The surface 34 of the blade gear, extending from the center hole 33 to the side walls or skirt portion 85 thereof, slopes downwardly towards the center hole, as shown in Figs. 1 and 2, and bears against the lower surface of the resilient ring 21. The upper surface of the resilient ring 21 bears against the extreme end of the blade shank I6 and also against the sloping surface 86 on the lower end of the adapter I8. The surface 36 of the adapter I8 is sloped at a greater angle than the surface 34 of the blade gear, and the resilient ring 21 engaging these surfaces is, therefore, thicker at the edges than at the center.

In assembling the above-described units, the ring 24, the blade gear 26, the resilient ring 21, in the order named, are placed on the shank 23 of the T-bolt 2l, and the adapter I8 is then threaded onto the threaded portion thereof. The

adapter I8 is tightened on the T-bolt 2| until the resilient ring is slightly compressed, after which a locking pin such as 81, Fig. 1, may be inserted in a hole formed between the cooperating threads of the adapter I8 and the T-bolt. The pin 31 has a fiat head 33 which is anchored by screws such as 4I to the adapter I8 and the upper end of the T-bolt.

Prior to the placing of the blade gear 26 on the T-bolt carrying the ring 24, a pair of diametrically opposite feather keys 42 are inserted in radial holes in the walls of the counterbore 86 of the blade gear with the heads 44 of the keys extending into the counterbore. The heads 44 are fiat-sided and cooperate with axial grooves 46 in opposite sides of the ring 24. The keys 42 thus keep the ring 24 from rotating relatively to the blade gear 26 about the central axis thereof, while at the same time permitting the cylindrical surface 3I of the ring to roll on the fiat surface 32 forming the end of the counterbore in the blade gear. This rolling motion of the ring 24 on the gear 26 is in the plane of the elements as shown in section in Fig. 2, which is perpendicular to the plane in which the T-bolt is permitted to roll on ring 24, as previously described, which is in the plane of the elements as shown in Fig. l. Obviously, these planes will always remain in the same relatlveposltion to each other regardless of the rotation of gear 26 about its central axis. Accordingly, the T-bolt 2| through a combination of the two described rolling movements in intersecting planes is free to swing in any direction relatively to the blade gear 26, the axis of which is substantially radial to the axis of the central hub bore I2, and such swingingv is effected solely through direct rolling contacts betwen the described cooperating surfaces.

The blade gear 26, which is the power actuated v element by which the pitch of the propeller blade is changed, has a toothed segment 41 engaging the teeth of a gear 48, Fig. 1. The gear 48 is mounted concentrically with the propeller shaft or the axis of the bore I2 of the propeller hub II and may be rotated relatively to the propeller shaft or hub by any of the well-known propeller blade pitch changing mechanisms in order to alter the pitch of the blade I6. The toothed segement 41 of the blade gear is of suilcient extent to provide the maximum amount of desired pitch changing movement of the blade, and since each blade mounted in the hub II will have a blade gear segment such as 41 engaging the gear 48 the pitch of all the blades will change equally and simultaneously. It will be noted that rotative movement of the gear 48 is transmitted without lost motion through the blade gear 25, the ring 24, the T-bolt 2l and the adapter I8 to the blade shank I6; the blade shank I6 being coupled to the adapter I8 to rotate therewith by means of the inter-engaging threads and a locking pin 43, Fig. 2, or other convenient means. Thus, the described universal blade anchoring arrangement in no manner whatsoever interferes with the accuracy of operation of the blade pitch changing mechanism.

The blade gear 26 may be mounted in the propeller hub socket I3 by any of the well-known arrangements. In the arrangement illustrated, the blade gear has a flange or circular shoulder 5I thereon which engages the lowermost of the inner races 52 of a stack of ball thrust bearings, the outer races of which are supported by the hub I I through the medium of a nut 56 threaded into the blade socket I3. The bore oi' the socket I8 is substantially radial to the central hub bore I2. The thrust bearing 52-58 is thus adapted to permit rotation of the blade gear 26 about a substantially radial axis and to retain it against the action of centrifugal and other forces which are exerted upon it during rotation of the propeller.

When assembling the blade I6 to the hub II, it is evident that as the nut 56 is tightened, the

.thrust force developed thereby is transmitted through the thrust bearing 52-53 to the blade gear 2-6. This force on the blade gear is translmitted through the ring 24 to the T-bolt 2|, the

head of which may bear against a piece of resilient material 55 of suitable characteristics supported by the portion of the hub II surrounding the propeller shaft bore I2. By this means, the thrust bearing and the rolling contact surfaces of the parts 2i, 24 and 26 may be preloaded.

A packing ring 51 substantially rectangular in cross-section may engage the lower outside sur face of the nut 56, while another packing ring 58 having a U-shaped cross-section may engage the lower inside surface of the nut 56 and the outer surface of the upper end 35 of the blade gear 26. The packing rings 5l and 53 are for the purpose of preventing the escape of lubricant carried in the blade socket, and the ring 2i may cooperate with the packing rings 51 and 53 .in this respect. Located above the packing ring 56 and engaged on its lower side thereby is a buffer ring 59 of pliant material such as rubber which has secured to the inner surface thereof, as by means of a vuicanizing process, a metal sleeve 6I which fits slidably about the lower end of the blade shank I6. The ring 6I permits rotation of the blade i6 about its longitudinal axis without chafing or scuing of the rubber buffer ring 59. The buffer ring 59 yieldably supports the blade against transverse movement, thus tending to hold the longitudinai axis of the same coincident with the axis of the hub socket I3. During acceleration of the propeller and while the forces acting thereupon are changing and thus causing the blade to swing from one position of equilibrium to another, the buffer ring 53 will act t0 prevent any clashing or objectionable impact which might otherwise occur between relatively moving parts connected with the blade and the hub.

The buffer ring 59 is held in the blade socket by an offset clamping ring 62 which in turn is secured to the upper end of the blade socket by screws such as 63. The screws 68 may also hold in position one or more keys such as 64 located in radial slots such as 66 and 61 in the upper 7 surfaces of the socket I3 and the nut 58. respectively. I'he keys 84 prevent movement of the nut 58 relatively tothe socket I 3.

When mounting a blade in a socket such as I8,

` the clamping ring 62. the buffer ring assembly 59-8I, the packing ring 58, and the nut 58 are lslipped over the blade shank I6, following which the sub-assembly consisting of the adapter I l, the ring 21. the blade "gear 26 with the thrust bearing 52--53 thereon, the ring 24, and the T-bolt 2i are attached to the blade shank I8 by means of the internal threads I1 thereof engaging the external threads of the adapter I8. 'I'he adapter I8 is locked to the blade shank I6 by the pin 49, which passes through the lower wall of the blade shank into the adapter. The pin 49as shown in Figs. 2, 5 and"6, is held in place by screws such as 88 and an opening such as notch 89 is provided in the upper end of the blade gear to permit the insertion of the pin 49. The blade shank -IB with the associated elements secured thereto is next placed in thevsocket I3, following which the nut 56 is threaded into the socket and tightened to the desired extent. Next the clamping ring 62 is secured firmly against the buffer ring 59 by screws 63 inserted in the upper end of the socket I3.

In accordance with the above, it is obvious that a propeller blade mounting arrangement is provided which permits free universal swinging of the blade relatively to the propeller hub within predetermined limits, and that such swinging movement is accomplished without any sliding solely through the medium of two free rolling motions, in relatively xed intersecting planes, which may be at 90 degrees or other suitable angle to each other. It is equally obvious that there is nothing in the arrangement shown which in any way limitsr its application to propeller mechanisms. On the contrary, as previously emphasized herein, the universal joint construction covered by the present invention is applicable in any art or industry where relatively heavy longitudinal loads are required to be transmitted through universal joints, and also where torque loads may be required to be simultaneously transmitted. A propeller blade mounting has, therefore, simply been used to illustrate the principles and general method of construction included in the invention.

A propeller blade mounting of this type is particularly advantageous, because it permits the blade to freely adjust itself with relation to the axis of its socket, without danger of abrading any contact surfaces, and in this way automatically eiect a balance between the opposing moments exerted on it, by aerodynamic and centrifugal forces, thus eliminating or greatly reducing the bending stresses exerted on its shank.

A modification of the above described .blade mounting is shown in Figs. 7 to 10, where there is illustrated an articulated joint which provides for swinging motion of a propeller blade through rolling movement in a single plane. This arrangement is desirable because of its simplicity, but it is not as eiective in reducing blade shank stresses as a universal type of mounting. In the modification, the propeller hub and blade shank are in all substantial respects similar to those in the preferred'embodiment and are accordingly referred to by similar reference numerals. 'I'he blade gear 1I, Figs. '1 and 8, has a segment with teeth 12 thereon engaging the gear 13 operated -by the pitch changing mechanism in the usual ter hole therethrough. and a cylindrical surface 14 formed across the lower side thereof. The shank of a T-bolt 15 extends through the center hole of the blade gear with the iiat surface 16 on the inside oi' the head thereof engaging the cylindrical surface 14 `on the blade gear. Depending flanges such as 11 on the blade gear engage opposite sides of the head of the T-bolt 15 to prevent the same from rotating relatively to the .blade gear .about the central axis thereof. The threaded upper end of the T-bolt is engaged by the internal threads of an externally and internally threaded adapter 18, and the two units are locked together by means of a locking pin 19. The external threads oi the adapter 18 engage internal threads at the lower end of the shank I6 of theblade, and the blade is prevented frori'moving relatively to the adapter by a locking pin- The blade gear 1I-is supported in the blade socket in the usual manner by a substantially radial thrust bearing such as 82; the thrust bearing in turn being held in the hub socket I3 by a nut 83 having threaded engagement therewith. The nut 83` may be locked in place by one or more keys such as v84 extending across radial grooves such as 86 and 81 in the upper surface of the socket and the nut. The keys 84 may be held in place by screws such as 89, which also secure a ring 89 to the top of the blade socket that retains a resilient buier ring 9| of rubber or similar material. The buffer ring 9I is supported by a sleeve 92 which is secured to and adapted to rotate with the upper tubular portion of the blade gear 1I, so that when the blade pitch is altered there is no chailng action between the buffer ring and blade shank.

'Ihe blade socket may also be provided with the usual packing rings 94 and 95 which prevent the leakage of lubricantat the upper end of the socket, and a third packing ring 96 placed in a groove in the blade gear 1I will engage the shank of the T--bolt 1'5 to prevent leakage of lubricant at that point. As in the preferred embodiment the hub may be provided with resilient material such as 91 engaging the head of the T-bolt 15 whereby the thrust bearing and rolling contact surfaces 14 and 16 may be preloaded.

With elements of the blade mounting in the position shown in Fig. 7, it is obvious that the blade may swing in the plane of the section, and that this plane is fixed relatively to the gear 1I. Consequently, the blade is always free to swing in -this plane, the position of which is never changed with respect to the gear 1I but is altered with respect to the hub as the gear 1I is rotated to eiect pitch changes of the blade. It is also obvious that the swinging motion of the blade is accomplished solely through the rolling of the surface 16of the T-bolt 15 on the surface 14 of the gear 1I, and that at no time is there any sliding between these surfaces which coact to retain the blade against the centrifugal force exerted on it during rotation of the propeller. Furthermore, any turning orvtorque force exerted by the gear 13 on the gear 1I is transmitted without lost motion to the blade shank I6 through the medium of the T-bolt 15 and the adapter 18, because all of rthese members are secured against relative rotation about the central axis of theh'ub socket I3 in the manner previously described herein.

It will be obvious to those skilled in the art that various other modifications of the invention bemanner. The blade gear 1I has atapered cen-` I6 sides those shown and described herein may be member rotatably carried by said bearing, a sec-V ond member disposed at least in part radially lnward of said first member supported by andengaging said first member, said members having relatively convex abutments in rolling engagement with one another to sustain radially exerted.

forces due to said blade, and means passing freely through said first member, at least in part, connecting said blade and said second member` 2. In a variable pitch propeller comprising a hub and a blade, blade retaining means in said hub comprising a substantially radial thrust bearing, a iirst member supported thereby having an abutment, a second member having two abutments one engaging said first member abutment, a third member having an abutment engaging the second abutment of said second member, said engaged abutments being relatively cylindrically convex and being in rolling engagement with their neighbors, and means securing said blade to said third member, said relatively convex pairs of abutments respectively being constructed for rolling engagement each in a single plane, said planes being substantially at right angles to one another.

3. In a variable pitch propeller comprising a hub and a blade, blade retaining means in said hub comprising a substantially radial thrust bearing, a first member supported thereby having an abutment, a second member having two abutments one engaging said first member abutment, a third member having an abutment engaging the second abutment of said second member, said engaged abutments being relatively cylindrically convex and being in rolling engagement with their neighbors, means securing said blade to said third member, said relatively convex pairs of abutments respectively being constructed for rolling engagement each in a single plane, said planes being substantially at right angles to one another, and means to constrain said members and blade for unitary rotation relative to said hub substantially about the blade axis.

4. In a variable pitch propeller comprising a hub and a blade, blade retaining means in said hub comprising a substantially radial thrust bearing, a iirst member supported thereby having an abutment, a second member having two abutments one engaging said first member abutment,

a third member having an abutment engagingl the second abutment of said second member, said engaged abutments being relatively cylindrically convex and being in rolling engagement with their neighbors, means securing said blade to said third member, said relatively convex pairs of abutments respectively being constructed for rolling engagement each in a single plane, said planes being substantially at right angles to one another, means to constrain said members and blade for unitary rotation relative to said hub substantially about the blade axis, and gear means engaging the bearing supported member for rotating said members and blades unitarily substantially about the blade axis to alter blade pitch.

5. In a variable pitch propeller comprising a hub and a blade, blade retaining means in said hub comprising a substantially radial thrust bearing. a first member supported thereby having an abutment, a second member having two abutments one engaging said iirst member abutment, a third member having an abutment engaging the second abutment of said second member. said engaged abutments being relatively cylindrically convex and being in rolling engagement with their neighbors, means securing said blade to said third member. said relatively convex pairs of abutments respectively being constructed for rolling engagement each in a single plane, said planes being substantially at right angles to one another, and resilient means engaging said blade and first member for urging said blade to a substantially radial position relative to the hub axis 'to resist articulating movement of said blade on said relatively convex abutments.

6. In a variable pitch propeller comprising a hub and a blade, blade retaining means in said hub comprising a substantially radial thrust bearing, a first member supported thereby having an abutment, a second member having two abutments one engaging said first member abutment, a third member having an abutment engaging the second abutment of said second member, said engaged abutments being relatively cylindrically convex and being in rolling engagement with their neighbors, means securing said blade to said third member, said relatively convex pairs of abutments respectively being constructed for rolling engagement each in a single plane, said planes being substantially at right angles to one y another, and means for preloading said abutments into firm engagement with one another.

'7. In an articulated mounting for a blade on a variable pitch propeller hub having a blade socket, a retention member secured within and rotatable relative to the socket, said member having an opening substantially coaxial with the socket and an inwardly facing abutment, a thrust member having an outwardly facing abutment engaging the member abutment, said abutments being relatively convex and rollable without sliding on one another about an axis substantially normal to the blade axis, and means freely passing through said retention member opening and securing said thrust member and said blade.

8. In an articulated mounting for a blade on a variable pitch propeller hub having a blade socket, a retention member secured within and rotatable relative to the socket, said member having an opening substantially coaxial with the socket and an inwardly facing abutment, a thrust member having an outwardly facing abutment engaging the member abutment, said abutments being relatively convex and rollable without sliding on one another about an axis substantially normal to the blade axis, means freely passing through said retention member opening and securing said thrust member to said blade, and means to constrain said blade and retention member against relative rotation about the blade and socket axis.

9. In an articulated mounting for a blade on a variable pitch propeller hub having a blade socket, a retention member secured within and rotatable relative to the socket, said member having an opening substantially coaxial with the socket and an inwardly facing abutment, a thrust member having an outwardly facing abutment engaging the member abutment, said abutments being relatively convex and rollable without sliding i a variable pitch P IQpellcr hub havingmeans'for Y mounting Aabla'sie 'fcrfnitch .changera irst member-' 'rotatable` -relative to'saidfmeans having can y blade to unitary rotation" with vone another rela tive to said blade mounting means. 1

l l2 on one another about'an axis substantially nor- 12. -In an articulated mounting for a blade on mai to the blade axis, means freely passing a variable' pitch propeller hub having meansfor through said retention member opening and semounting a blade for pitch changea iirst memcuring said thrust member to said blade. and reber rotatable relative to said means having insilient means engaging said blade and said reten- 5 wardly facing abutments spaced from one antion member to urge said blade toward a radial other in a direction normal to the blade, axis, a position relative to said socket. second member inwardlyl disposeQelative to said 10. In an articulated mounting for a blade on a first member having spaced abutnrents respecvariable pitch propeller hub .having means for tively engaging said spaced inwardly iacing abutmounting a blade for pitch change, a iirst meml0 ments, the engaged abutments .being relatively ber rotatable relative to said means having an convex and said members being rollable on one inwardly facing abutment, a second member inanother through a limited angularrange about wardly disposed relative ,-to -said first vmember an axis substantially normal to sai'd blade axis, having an abutment engaging said first member said second member having inwardly facing abutabutment, said abutments being relatively con- 15 m nts spaced from one another in a direction vex and said members being rollable on one ansustantially normal to the blade axis. a third other through a limited angular range aboutan member inwardly disposed relative to said ilrst axis substantially normal to said blade axis. said 1 and second members having spaced abutments second member having anv inwardly facing abutrespectively engaging the spaced inwardly facing ment, a third member inwardly disposedv relative 20 abutments of said second member, said second to said first and second members having an abut-,- and third member engaging abutments being re1- ment engaging the inwardly. facing abutment of atively convex and said members being rollable on the second member, said second and,thirdjinelrbone another througha limited angular range ber engaging abutments being relatively convex y about an axis substantially normal to the blade and said members being rollable on one another axis and substantially normal to thflrst rolling through al-limited angulargjrange aboutanaxis Aaxis, and means passingv between the several sets substantiallynormal to the 'blade axisfandgsubi of' spacedv abutments securing said third member stantiallyjnormal i-to'theflrst' rollingaxis. fandU ov said blade. means securing,- said third member to saidbiadej- Y Y `HOW` MURPHY.

f nEFEaENcEs CITED 1,1.f'1n an arncuiated'mountingfor-a'blade on* 'lfheffollowingfreferenloes are of record 4inthe ,fitmvspatent I i UNITEDYSTATES PATENTS 1' inwardly racingl abutment, a ,second member 111+ wardly disposed relative to said rst member-having ant abutment engaging, said iirst memberv g mme` Date i abutment. saidfabutmenis -being relatively'conf l Dnham Apr I, 1919 vex and said members beingvrollable on one.. answe-ney T'- "v-'l Apr. 1926 otherthroush a limitedanguiar rangeabout an ,Powers "Nv 16' 1926 axis substantially normal to and blade :ana-said y' 1 mehr ann 2a 1927 second member having @n lnv'rdlyiacingabutf Heath Apr 28'. 1931 ment, a thirdmemberinwardly@disposedrrela- Ag 8.' 1933 y third member engagingabutments-beingrelativl A11-stm l m55-1939 ly convex and said members being rollable'on" fe Chuton.'"' May 6 1941 another through a-v limitedansularrange-about Y Chinon "31m e 10 1941. an axis substantially normal tothebladea'xisand Reissue; i. Mar 3' 1942' substantially normal to z the'ziilrst rolliri'gmrig 6 v, v --f v means securing said third member to said plage, w l l FOREIGN .PATENTS 1 and lmeans to constrainsaidathreemembersjand a country Date Great' Britain Apr. 14, 1921 

